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148 lines
3.0 KiB
C++
Executable File
148 lines
3.0 KiB
C++
Executable File
#include <math_NewtonFunctionRoot.ixx>
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#include <math_FunctionWithDerivative.hxx>
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math_NewtonFunctionRoot::math_NewtonFunctionRoot (math_FunctionWithDerivative& F,
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const Standard_Real Guess,
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const Standard_Real EpsX ,
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const Standard_Real EpsF ,
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const Standard_Real A,
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const Standard_Real B,
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const Standard_Integer NbIterations ){
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EpsilonX = EpsX;
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EpsilonF = EpsF;
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Binf = A;
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Bsup = B;
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Itermax = NbIterations;
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Done = Standard_False;
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X = RealLast();
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DFx = 0;
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Fx = RealLast();
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It = 0;
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Perform(F, Guess);
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}
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math_NewtonFunctionRoot::math_NewtonFunctionRoot (const Standard_Real A ,
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const Standard_Real B,
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const Standard_Real EpsX ,
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const Standard_Real EpsF ,
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const Standard_Integer NbIterations ){
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Binf = A;
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Bsup = B;
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EpsilonX = EpsX;
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EpsilonF = EpsF;
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Itermax = NbIterations;
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Done = Standard_False;
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X = RealLast();
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DFx = 0;
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Fx = RealLast();
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It = 0;
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}
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math_NewtonFunctionRoot::math_NewtonFunctionRoot (math_FunctionWithDerivative& F,
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const Standard_Real Guess,
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const Standard_Real EpsX ,
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const Standard_Real EpsF ,
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const Standard_Integer NbIterations ){
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EpsilonX = EpsX;
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EpsilonF = EpsF;
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Itermax = NbIterations;
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Binf = RealFirst();
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Bsup = RealLast();
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Done = Standard_False;
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X = RealLast();
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DFx = 0;
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Fx = RealLast();
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It = 0;
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Perform(F, Guess);
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}
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void math_NewtonFunctionRoot::Perform(math_FunctionWithDerivative& F,
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const Standard_Real Guess) {
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Standard_Real Dx;
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Standard_Boolean Ok;
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Standard_Real AA, BB;
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//--------------------------------------------------
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//-- lbr le 12 Nov 97
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//-- la meilleure estimation n est pas sauvee et on
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//-- renvoie une solution plus fausse que Guess
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Standard_Real BestX=X,BestFx=RealLast();
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//--
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if ( Binf < Bsup) {
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AA = Binf;
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BB = Bsup;
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}
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else {
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AA = Bsup;
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BB = Binf;
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}
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Dx = RealLast();
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Fx = RealLast();
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X = Guess;
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It = 1;
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while ( (It <= Itermax) && ( (Abs(Dx) > EpsilonX) ||
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(Abs(Fx) > EpsilonF) ) ) {
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Ok = F.Values(X,Fx,DFx);
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Standard_Real AbsFx = Fx; if(AbsFx<0) AbsFx=-AbsFx;
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if(AbsFx<BestFx) {
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BestFx=AbsFx;
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BestX =X;
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}
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if (Ok) {
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if (DFx == 0.) {
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Done = Standard_False;
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It = Itermax + 1;
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}
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else {
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Dx = Fx/DFx;
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X -= Dx;
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// Limitation des variations de X:
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if (X <= AA) X = AA;
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if (X >= BB) X = BB;
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It++;
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}
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}
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else {
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Done = Standard_False;
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It = Itermax + 1;
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}
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}
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X = BestX;
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if (It <= Itermax) {
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Done = Standard_True;
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}
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else
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{
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Done = Standard_False;
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}
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}
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void math_NewtonFunctionRoot::Dump(Standard_OStream& o) const {
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o <<"math_NewtonFunctionRoot ";
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if (Done) {
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o << " Status = Done \n";
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o << " Location found = " << X <<"\n";
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o << " function value at this minimum = " << Fx <<"\n";
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o << " Number of iterations = " << It <<"\n";
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}
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else {
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o << "Status = not Done \n";
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}
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}
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